Rubber-to-metal adhesions



18f7 1945- l G. F. ROQUEMORE 2,381,186

` RUBBER-TO-METAL ADHESION .l

Filed Nov. 5, 1942 www Patented Aug. 7,` 1945 RUBBER-To-METALADHESIONS. Glen F. Boquemore, Akron, 0h10, assignor to Wingi'oot Corporation, Akron, Ohio, a

tion ot Delaware 'Appllcation November 3,1942, Serial No. 464,424

2 claims. (ci. 154-43) l'his invention relatessto rubber-to-nietal adhesions.

In the past, manyattempts have been made to iind a satisfactory adhesive for bonding rubber to metals, such as aluminum, steel, brass, copper, nickel, cadmium, etc. Rubber adheres to brass, copper, nickel, and cadmium more readily than to aluminum and steel. However, the bonding oi' rubber to any of these materials has presented a problem. Although various bonding agents have been used, the search is still being continued for a satisfactory bonding material whichdoes not become plastic at temperatures of 200 C. or above after the bond has been formed.

This invention relates to the formation of such a strong bond which remains strong when heated. The invention includes the bonded materials as well as the process of producing them. In the accompanying drawing, Flg. l is a plan view of a laminated structure, illustrating the invention, in which a portion of the structure is cut away to show the various layers therein. Fig. 2 is a, section along the line 2--2 in 1 Referring to the drawing, I is a layer of metal to which a layer of rubber 3 is bonded by means of a bonding layer 2.

According to this invention, rubber is united to metal by an adhesive which is composed to a large extent of cyclized rubber to which a diisocyanate has been added. The cyclized rubber may be one of the Pliolite products manufactured by The Goodyear 'I'lre 8 Rubber Company and formed by cyclizing'rubber,. uslng .tin tetrachloride or chlorostannic acid or thel like as the ene diisocyanates, the dimethyl phenylene diisocyanates, the naphthyl diisocyanates, the diisocyanates of dioxane, hexamethylene diisocyanate, etc. These diisocyanates may be prepared by treating a solution of the corresponding diamine with an excess of hydrogen chloride and then introducing phosgene into the resulting mixture of precipitated amine hydrochloride, and solvent.

' cyanate may be as low as 10 per cent or as high cyclizing agent. .The adhesive may be any other A cyclized rubber, 'such asI that produced by treating rubber with s. phenol sulphonic acid to produce compounds as those known in the trade as Thermoprene and Vulcalock (both manufactured by B. F. Goodrich Company, Akron, Ohio), Marbon B (manufactured by Marbon Corporation of Gary, Indiana, apparently according to U. 8.

2,230,359), etc. Any mused rubber adhesive composition containing' an organic diisoeyanste isocrmtu. dim pnesylenenomulte). etbylmediicsu isocranltehmdjbedlimamtesorothsrslycol etnm.th ediisocnnstesctmyl mm1.

as 40 per cent or higher based onthe solids con- .tent of the adhesive. In one instance the addition of 30 per cent of a diisocyanate wasi'ound to practically double the adhesion at`200 F. Even less than 10 per cent of the diisocyanate gives improved adhesions.

' The rubber is rst compounded with vulcanizing ingredients. Then either the surface of thei unvulcanized slab of rubber or the surface of the' metal or both are treated with the cyclized rubber adhesive containing the diisocyanate. The cyclized rubber may be alone or it maycontain other compounding ingredients, such as plasticizers, etc. A satisfactory coating compositie has the following formula: Y

Parts Rubber 100 Memaptobenzothiazole 0.75 Sulfur A2.8 Stearlc'acid 30 Pine ltar f 3.0 Phenyl beta naphthylamine 1.0 Zinc oxide 5.0 Carbon black.. 50.0

wnatIclsim-isz,

1. .An article-comprising a rubber part and a Umetal part and, therebetween, a bonding layer comprising a maior proportion of a cyclized rub` ber adhesive and a minor proportion of an organic diisocyanate.

2. an mais comprising -srubber part slug:

wmvrlllns e maior. proportion of s ey 1.. ber adhesive and a minor proportion of methylene r. aooomoar. 

